Hadi H. Jaafar

Impact of the Syrian conflict on irrigated agriculture in the Orontes Basin

The impact of conflict on irrigated agriculture and consequently summer crop production within conflict-affected agricultural lands was observed in the Orontes Basin. Water and energy use were reconfigured through a transition from rainfed to irrigated agricultural production over the past 20 years, but have been disrupted as the Syrian war has unfolded since 2011. Remotely sensed vegetation indices were used to determine irrigated summer crop yields during the year 2013. Findings suggest that irrigated agricultural production dropped between 15% and 30% in the Syrian portion of the basin in 2000–2013, with hotspots identifiable in Idleb, Homs, Hama, Daraa and Aleppo. The developed approach demonstrated effectiveness in quantifying and geolocating hotspots where conflicts have the strongest impact on agricultural water use, agricultural production, and eventually support relief and regional agricultural reconstruction in this and other conflict regions.

Crop yield prediction from remotely sensed vegetation indices and primary productivity in arid and semi-arid lands

Global demands for biomass and arable lands are expected to double in the next 35 years. Scarcity of water resources in arid and semi-arid areas poses a serious threat to their agricultural productivity and hence their food security. In this study, we examine whether crop yields can be predicted from remotely sensed vegetation indices and remotely sensed estimates of primary productivity. Spatial relationships between remotely sensed enhanced vegetation index (EVI), net photosynthesis (PNet), and gross and net primary production (GPP and NPP, respectively) in irrigated semi-arid and arid agro-ecosystems since the beginning of the century are analysed. The conflict-affected country of Syria is selected as the case study. Relationships between EVI and crop yield are investigated in an effort to enhance food production estimates in affected areas outside governmental jurisdictions. Estimates of NPP derived from reported irrigated agriculture crop data in a semi-arid and an arid zone are compared to remotely sensed NPP in a geospatial environment. Results show that winter crop yields are correlated with spring GPP in semi-arid zones of the study area (R2 = 0.85). Summer crop yield can be predicted from either cumulative summer EVI (R2 = 0.77) or PNet in most zones. Where fully irrigated fields are surrounded by hyper-arid landscape, summer PNet was negative in all instances and EVI was inversely correlated with yield. NPP from crops was much higher (290 gC m−2 year−1) in those regions than MOD17 NPP (70 gC m–2), where 1.0 g of carbon is equivalent to 2.2 g of oven-dry organic matter (= 45% carbon by weight). The gap was less in semi-arid zones (2–39% difference). Overall crop-derived NPP for the period 2000–2013 was 322 versus 300 gC m–2 for that remotely sensed within the cropped zones of the political units. The results of this study are crucial to derive accurate estimates of irrigated agriculture productivity and to study the effect of the latter on net ecosystem carbon storage.

High-Resolution Method for Modeling Hydraulic Regime Changes at Canal Gate Structures

A method for modeling flow regime changes at gate structures in canal reaches is presented. The methodology consists of using an approximate Riemann solver at the internal computational nodes, along with the simultaneous solution of the characteristic equations with a gate structure equation at the upstream and downstream boundaries of each reach. The conservative form of the unsteady shallow-water equations is solved in the one-dimensional form using an explicit second-order weighted-average—flux upwind total variation diminishing (TVD) method and a Preissmann implicit scheme method. Four types of TVD limiters are integrated into the explicit solution of the governing hydraulic equations, and the results of the different schemes were compared. Twelve possible cases of flow regime change in a two-reach canal with a gate downstream of the first reach and a weir downstream of the second reach, were considered. While the implicit method gave smoother results, the high-resolution scheme—characteristic method ...

Water productivity of Origanum syriacum under different irrigation and nitrogen treatments using an automated irrigation system

Limited water supplies in semi-arid and arid regions are limiting crop production and profitability. Lebanese Oregano (Origanum syriacum) is a perennial herb of the Lamiaceae (mint) family that has high commercial and medicinal potential, with little known about its water requirements. A four-replicate split-plot field study was conducted during 2013–2014 in the Beqaa Valley in Lebanon to determine the yield response of Origanum syriacum to different levels of drip irrigation and evapotranspiration (ETc), and to document its growth parameters and soil water use. Four irrigation treatments were automatically set by applying 60%, 80%, 100% and 120% of Hargreaves ET as calculated by a commercial irrigation controller and weather station. Flowmeters were used on the four treatments and the irrigation amounts were measured. Results show that total fresh and dry yield as well as dry leaf yield significantly decreased with decreasing %ET. The highest ET treatment gave the highest fresh and dry yield and dry leaf yield but the lowest dry/fresh yield ratio. The 60% ET was significantly lower than all other treatments. No significant difference was found among the 60% and the 80% ET treatments. Water use efficiency increased significantly as irrigation decreased. Water productivities were highest (0.97 kg/m 3 ) for the lowest irrigation treatment (vs. 0.70 kg/m 3 for the highest irrigation treatment).

Prioritization of Small and Medium Domestic Dams in Dry Lands

AbstractThe feasibility of small and medium dams in arid environments is studied. A novel method for prioritization of dam commissioning is proposed. The method focuses on key hydrologic and economic factors that affect the investment decision-making process. Ranking for priorities is developed in a geographic information system (GIS)-aided environment. Evaluated parameters are based on extensive field data including topographic surveys and site visits, land cover and soils data, precipitation data, runoff data, demography, construction costs, and operation and maintenance costs. Reservoir yield, reliability, and annualized cost per satisfied demand are the three main criteria used in the methodology. Results of a case study on 12 proposed dams in Assir Region, Saudi Arabia, indicate that assessment of these criteria is crucial prior to investment decision-making in arid areas. More than three quarters of the small and medium dams proposed have been found to have a high cost of water productivity and very...